What Does China’s Mysterious, Uniquely Designed ‘Trimaran’ Submarine Signal to the World?

China is currently building new classes of submarines at a faster pace and in greater numbers than any other country. It is pursuing several ambitious projects to expand its dominance beneath the seas. However, a highly unusual submarine recently spotted in the Chinese naval fleet has sparked intense curiosity among technology and defence analysts. It is not an ordinary underwater vessel but a unique submarine featuring a three-hull, or “trimaran”, design, a world first.

According to defence analysts, the warship will patrol silently beneath the Pacific Ocean, with only a snorkel mast visible above the water. After receiving encrypted messages from satellites indicating the location of a distant enemy, it will surface. Its unique trimaran, or three-hull, structure is expected to provide exceptional stability on the water’s surface.

As soon as it surfaces, two large hangars built into its main structure will open, revealing 16 missile tubes. An enemy carrier strike group located approximately 1,500 kilometres (930 miles) away could then become a target within moments.

Mysterious Location and Unusual Design

The submarine was previously described as a “semi-submersible arsenal ship”, but it has not been officially given a name or a Western designation. It is currently undergoing highly secretive testing and trials at the Chinese naval base in Huludao, in the Bohai Sea. Built in the southern Chinese city of Guangzhou earlier this year, the vessel was transported north through the port of Dalian.

Researchers analysing open-source intelligence (OSINT) and satellite imagery have concluded that the vessel belongs to an entirely new category of warship. According to their assessment, it is a “submersible warship” designed to travel covertly underwater to a concealed location. However, it must surface before deploying its weapons or launching missiles.

16 Destructive Missiles and New Technology

The central section of the Chinese submarine contains at least 16 powerful missile tubes. Satellite imagery analysis indicates that they are arranged horizontally inside the hangars in two circular clusters. To launch its weapons, the submarine must surface, open the hangar doors and raise the missile tubes into a vertical position.

It is believed that the vessel will carry powerful anti-ship missiles or missiles capable of striking land targets. Since the missiles will be launched after the vessel surfaces, there is considerable speculation that it could use the advanced YJ-20 hypersonic missile, which is commonly associated with China’s Type 055 destroyers.

The Mystery of Its Uncrewed Operation and Trimaran Structure

Dr Rachel Palling, principal consultant at K39 Consulting and a specialist in ship design, believes the new submarine is unlikely to carry a conventional crew.

“This warship can displace approximately 900 tonnes of water when submerged. The weapons and large hangars occupy most of the vessel, leaving virtually no space for living quarters,” she said. “There is an open bridge on top of the vessel, but it is used for remote human control when entering or leaving port, a feature commonly seen on large uncrewed surface vessels (USVs).”

Its trimaran, or three-hull, configuration is designed to maintain stability while travelling on the surface and during missile deployment. The vessel reportedly has a snorkel system to support diesel-engine operation underwater, alongside electric propellers and pump-jet propulsion.

A Cold War Legacy and Modern Naval Warfare

According to Dr Palling, the design philosophy behind the new warship recalls the Soviet Union’s Juliet-class cruise missile submarines from the Cold War era. Those diesel-powered submarines also surfaced to launch missiles.

China’s new design, however, is considerably more modern. The extended range of advanced hypersonic missiles could allow it to launch attacks from far across the ocean while remaining difficult to detect. It could function as a floating transporter and launch platform connected to China’s central network, enabling it to evade enemy surveillance, carry out sudden, large-scale missile strikes and quickly withdraw.

China has yet to publicly disclose details of the mysterious project. Defence experts nevertheless believe the unconventional trimaran submarine could significantly alter the tactics and balance of modern naval warfare.